Hello native english speakers!
I wonder if I can say go upstairs to my baby
When i am on the first floor and I only need her to move, or can i say come downstairs if I am at a lower place than the person I speak to.
One more question, when I am going to go across the street, what shall I say to my baby?
Thank you very much!

Yes, you can say "Go upstairs!" to people in English, its kind of an order when said like this.

We say "cross the road" or "cross the street" in English. If you are indicating something is on the other side though, you say "Across the road". For example "Let's cross the road" means you want to go to the other side of the road whereas "My friend is across the road" indicates your friends location. :-)

You can use 'come upstairs/downstairs/into the kitchen/etc...' if the other person is not in the same place as you, and you want them to be in the same area of the house as you are. Similar to 'come here'.

You can also use 'come (somewhere)...' if you are both in the same place and you want the other person to 'come with' you.

You can use 'go (to some place)' when a person is with you and you want them to go somewhere different.

You can use 'Lets go (somewhere)' if you want to go together with someone. You do not need to be in the same place, for example they could be upstairs, you could be downstairs and you say, 'Lets go outside'.

'Lets cross the road'
I hope together is implied.
I saw a parent allowing a child to lead him (the parent) across a busy road the other day. The child was at most 3 years old. Is it just me, or does anyone else think the parent should carry the child in that instance?

Blobble and tiger tiger, thank you very much. Without native speakers like you, I can only guess!

While it's commendable that you want to teach your child English from his/hers earliest years, please make sure that your pronunciation is good enough.

Ask your foreign friend to honestly assess your pronunciation.
I'm not saying that you should sound like some highly educated Brit speaking Queen's English, but what you say should at least be intelligible to a foreign person.

I think you're aware that most Chinese people have problems with English pronunciation, so before you start teaching your child- make sure you're teaching him/her right.

When it comes to learning languages- there is nothing worse than being taught erroneously.

Many people in China confuse pronunciation and accent. "Snack" is often pronounced "snake", in an immaculate American accent.

thank you Heniu. Pronunciation matters but it's not that important. See how many different dialects are there in china, Lots of Chinese children don't speak standard Chinese in their childhood, but many of them could speak great Chinese when they grown up. We can't wait for perfection. By the way, my pronunciation is better than most English teachers that's one of the reasons that I decided to teach my baby myself.

thank you Heniu. Pronunciation matters but it's not that important. See how many different dialects are there in china, Lots of Chinese children don't speak standard Chinese in their childhood, but many of them could speak great Chinese when they grown up. We can't wait for perfection. By the way, my pronunciation is better than most English teachers that's one of the reasons that I decided to teach my baby myself.

"Pronunciation matters but it's not that important"

And plenty of Chinese spend years of their lives learning an almost unintelligible form of English.

Good luck!

There are many tools you can use to learn a language. Try some TTS(Text to speech) programs that reads to you. You can imitate the pronunciation. Just type any sentence in the text area and it will read it to you nicely.